how long will it set around before it goes bad?
If you make the syrup concentrated enough, bacteria can't grow in it. I make 3:2 syrup and it keeps for months. I do add some apple cider vinegar to drop the pH.
You may still get some mold but the bees can deal with that. I understand that yeast are able to grow even in concentrated sugar water, so if you see white stringy material in the syrup, throw it out.
It may get lumpy. The mice may get into it. But it will keep as long as it doesn't get wet.
i made about 6 gals. wanted to make sure it would keep for a week or two. i bought a 5gal gas can and made a batch lol.
Just don't make the mistake of filling up your lawnmower with sugar water...
I use 5 gallon water cooler jugs, so I can see the syrup. A week or two won't be a problem.
thanks